The total /u01 mount point size is 105G where /u01/applprod/apps and /u01/applprod/inst instance directory exsits.
we have two directories
/u01/applprod - 57 GB
/u01/appldisc - 22 GB

Client is installed other monitoring tools under /u01 mount point it occupied another 20GB in this mount point. Later they have reliazed and delete all the monitoring tool files.
when we do df –h it still shows only 2.7 GB available and 97GB is occupied. The free space is not claiming after deleting the monitoring tool files.

Actually it should be 25GB availblae but it shows only 2.7GB is available.
Because of this insufficient space on /u01 the oracle application services are malfunctioning.